This invention relates to electric motors having encapsulated stators and rotors for protection while submerged in water.
The Patent to Fukushi et al. U.S. Pat. No. 4,492,889 discloses an encapsulated stator for a submerged motor having an inner cylindrical part made of carbon fiber-reinforced plastic which is adhesively bonded to metal end covers which are welded to an outer metal cylinder. The laminations and windings of the stator enclosed between the inner composite and outer metal cylinders are encapsulated by injecting a mold resin which can contain inorganic powder material into the volume enclosed by the cylinders. The composite inner cylinder provides increased wall thickness at opposite axial end portions to provide flawless joints between the inner composite cylinder and the end According to this patent the inner cylinder may be made from any plastic material or sheet metal and any suitable material may be used for adhesively bonding the cylinders together.
The Yamamoto et al. U.S. Pat. No. 4,496,866 discloses a submersible electric motor having a stator formed from an inner thin metal cylinder surrounded by a stator core and coil and a molded resin member formed to surround the outer wall having two end faces adhesively joined to the inner cylinder.
The Nakamura et al. U.S. Pat. No. 5,490,319 also discloses an electric motor with an encapsulated stator having a core and coils embedded in plastic resin with resin molded cans that isolate the encapsulating resin from the rotor section.
The Ineson U.S. Pat. No. 5,334,897 describes a sealed electric motor having interfitting metallic housing members and an overmolded plastic casing, and the Bresolin U.S. Pat. No. 5,767,606 describes a method for manufacturing a sealed synchronous electric motor, particularly for submersible pumps by which the entire stator of the motor is embedded into a matrix of insulating resin.